Australian Capital Gains Tax (CGT) Calculator
Estimate your capital gain, CGT discount, and potential tax payable in Australia.
General information only. This calculator is simplified and does not replace ATO guidance or professional tax advice.
How this capital gains australia calculator works
This calculator helps you estimate your net capital gain under Australian CGT rules. It combines your sale price, cost base adjustments, carried-forward losses, and eligible CGT discount, then applies your marginal tax rate to estimate potential tax.
It is useful for planning the sale of an investment property, shares, ETFs, managed funds, or other CGT assets. If you are comparing “sell now vs hold longer,” this gives you a practical first-pass estimate.
Core Australian CGT concepts you should know
1) Cost base
Your cost base is usually more than the amount you paid for the asset. It may include:
- Purchase price
- Stamp duty and transfer costs
- Legal and conveyancing fees
- Capital improvements (not routine repairs)
- Certain sale-related costs
A higher valid cost base usually means a lower taxable gain.
2) Capital proceeds
Capital proceeds are generally what you receive on sale. In practical terms, you should account for selling costs (agent commission, marketing, legal fees) when estimating your true gain.
3) Capital losses
Carried-forward capital losses can be used to reduce capital gains. In most cases, losses are applied before the CGT discount. If your losses exceed gains, the remaining loss may be carried forward.
4) CGT discount
If you hold an eligible asset for at least 12 months, you may qualify for a discount:
- Individuals and most trusts: 50% discount
- Complying super funds: 33.33% discount
- Companies: no CGT discount
This is why ownership period can significantly change your after-tax result.
Example: investment property CGT estimate
Suppose you bought for $550,000, paid $25,000 in purchase costs, spent $40,000 on capital improvements, and sold for $780,000 with $18,000 in sale costs. You held it 36 months as an individual and have $10,000 capital losses carried forward.
The calculator will:
- Calculate your gross capital gain
- Apply carried-forward losses
- Apply the 50% discount (if eligible)
- Estimate tax using your marginal rate
This gives you a realistic pre-lodgement estimate and helps with cash-flow planning.
Ways Australians legally reduce CGT
- Hold qualifying assets at least 12 months where practical.
- Keep thorough records of acquisition and improvement costs.
- Use valid carried-forward capital losses.
- Consider the timing of disposal across tax years.
- Model outcomes across ownership structures (individual, trust, company, SMSF).
Tax strategy should always be tailored. A licensed tax adviser can model scenarios using your full tax profile.
Common mistakes when calculating capital gains in Australia
- Forgetting purchase and sale transaction costs
- Mixing repairs with capital improvements
- Applying the CGT discount when not eligible
- Ignoring prior-year capital losses
- Using the wrong marginal tax rate assumption
Frequently asked questions
Does this calculator include the main residence exemption?
No. This tool is aimed at taxable CGT assets. Main residence rules and partial exemptions are complex and depend on your specific occupancy and usage history.
Is this accurate for shares and ETFs?
Yes, as a planning estimate. But for parcel-by-parcel accounting, reinvested distributions, and corporate actions, use your broker records plus professional tax support.
What if my result is a capital loss?
The calculator will show no tax payable and indicate a loss amount that may be carried forward (subject to Australian tax law requirements).
Final note
A good CGT estimate can save you from surprise tax bills and improve decision-making before you sell. Use this calculator as a planning tool, then confirm your final numbers using current ATO rules or a registered tax professional.